Look at your script and choose a setting in which to use your black lights, such as a scene where a party takes place or where glowing props or clothing illustrates a magical or transformational moment.
Test the black lights to ensure that you have enough lights at sufficient wattage to create the effect you want.
Hang the black lights toward the back of the stage if you would like them to reflect on the costumes or colors of the people on the stage.
Hang the black lights at the front of the stage, pointing toward the audience, if you would like to use them to shine on the audience to point attention to the entire theater or provide color for the audience.
Set the black lights on a remote to allow your stage hands to control them from off stage.
Design your costumes, props and set pieces with paint that is reflective under the black light. Neon paints or special black light paints are crucial to making items or characters stand out.